Solution structure of the Mesorhizobium loti K1 channel cyclic nucleotide-binding domain in complex with cAMP

Schünke, S.; Kaupp, U. B.; Stoldt, M.; Willbold, D.; Novak, K.

doi:10.1038/embor.2009.68

Journal Article

Solution structure of the Mesorhizobium loti K1 channel cyclic nucleotide-binding domain in complex with cAMP

Schünke, S.FZJ* ; Stoldt, M.FZJ* ; Novak, K.FZJ* ; Kaupp, U. B.FZJ* ; Willbold, D.FZJ*

2009
Nature Publishing Group London [u.a.]

EMBO reports 10, 729 - 735 (2009) [10.1038/embor.2009.68]

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Please use a persistent id in citations: doi:10.1038/embor.2009.68

Abstract: Cyclic nucleotide-sensitive ion channels, known as HCN and CNG channels, are crucial in neuronal excitability and signal transduction of sensory cells. HCN and CNG channels are activated by binding of cyclic nucleotides to their intracellular cyclic nucleotide-binding domain (CNBD). However, the mechanism by which the binding of cyclic nucleotides opens these channels is not well understood. Here, we report the solution structure of the isolated CNBD of a cyclic nucleotide-sensitive K(+) channel from Mesorhizobium loti. The protein consists of a wide anti-parallel beta-roll topped by a helical bundle comprising five alpha-helices and a short 3(10)-helix. In contrast to the dimeric arrangement ('dimer-of-dimers') in the crystal structure, the solution structure clearly shows a monomeric fold. The monomeric structure of the CNBD supports the hypothesis that the CNBDs transmit the binding signal to the channel pore independently of each other.

Keyword(s): Alphaproteobacteria: chemistry (MeSH) ; Crystallography, X-Ray (MeSH) ; Cyclic AMP: chemistry (MeSH) ; Cyclic AMP: metabolism (MeSH) ; Cyclic Nucleotide-Gated Cation Channels: chemistry (MeSH) ; Cyclic Nucleotide-Gated Cation Channels: metabolism (MeSH) ; Models, Molecular (MeSH) ; Potassium Channels: chemistry (MeSH) ; Potassium Channels: metabolism (MeSH) ; Protein Structure, Secondary (MeSH) ; Protein Structure, Tertiary (MeSH) ; Solutions (MeSH) ; Cyclic Nucleotide-Gated Cation Channels ; Potassium Channels ; Solutions ; Cyclic AMP ; J ; NMR solution structure (auto) ; MloK1 (auto) ; ion channels (auto) ; HCN (auto) ; CNG (auto)